The present invention relates generally to trailered vehicles. In particular, the present invention is a rescue sled adapted to be pulled by a traction vehicle, such as a snowmobile, for the purpose of transport of a patient and/or materials when conventional methods of transportation cannot be used due to climatic conditions or terrain limited accessibility.
Rescue sleds adapted to be pulled by a snowmobile over snow covered terrain are generally known. U.S. Pat. No. 3,746,357 to Haskins discloses one such ambulance sled. The ambulance sled includes an enclosed body shell having a rear end door to facilitate insertion and removal of a stretcher. The body shell is supported by a non-steerable rear ski unit. The rear ski unit includes a pair of skis attached by way of joints to the front and rear ends of leaf springs. The leaf springs are in turn pivotally attached to a cross-frame of the body shell for limited movement about a horizontal axis.
The ambulance sled further includes a steerable front ski unit. The front ski unit has a single ski which is attached by way of joints to a leaf spring. The leaf spring is in turn pivotally secured to the body shell through an attaching frame. A tow bar assembly, adapted to be secured to a snowmobile, is pivotally attached to the front ski unit. The tow bar assembly and front ski unit can swing forty-five degrees to either side of front and center. Because front and rear ski units of the ambulance sled of Haskins use leaf spring suspension assemblies, the ride of the ambulance sled can be somewhat rough, particularly at high speeds over rugged terrain. This rough ride, at the least, may be uncomfortable for the patient transported within the ambulance sled of Haskins, and at the most, could be traumatic.
The U.S. Pat. No. 4,389,066 to Weir et al. discloses another rescue sleigh that is adapted to be towed behind a snowmobile. The rescue sleigh includes a towbar section, a patient carrying section and an attendant's section. The patient carrying section is enclosed by a pivotally mounted canopy. Ski assemblies are secured via pivotal and movable bolt assemblies to frame members of the of the rescue sleigh. Each ski assembly includes a leaf spring means and a ski. As with the above described Haskins patent, the leaf spring suspension means of Weir et al. may cause the ride of the rescue sleigh to be somewhat rough at high speed over rugged terrain.
There is a need for improved rescue sleds. Specifically, there is a need for a rescue sled that can traverse rugged snow covered terrain at high speeds while providing a smooth and comfortable ride for a patient transported on the sled. In addition, there is a need for a rescue sled of efficient design and sturdy construction that can be towed behind a traction vehicle, such as a snowmobile, with minimal adverse affect to the rideability and steerability of the vehicle.